#1  
Old 08-11-2021, 01:05 PM
Tim Corcoran's Avatar
Tim Corcoran Tim Corcoran is offline
Ultimate Warrior
 
Join Date: Jan 2000
Location: Willow Spring, North Carolina
Posts: 4,666
Default China POS Master Cylinder

I purchased a replacement MC for my 65 LeMans bracket car. It's not the factory type it's a light weight aluminum unit and the previously one worked for many years. I have installed three in a row from O'Rileys Auto Parts and all three are bad. The port for the rear brakes won't build pressure but the one for the front brakes does. This is very frustrating how they can peddle this China garbage. I have posted pictures of the one I have so now I am looking for recommendations for a unit from another brand that maybe someone has had good luck with. Thanks.
Attached Thumbnails
Click image for larger version

Name:	Master Cylinder defective.jpg
Views:	168
Size:	42.5 KB
ID:	571133   Click image for larger version

Name:	Master Cylinder China POS.jpg
Views:	201
Size:	54.2 KB
ID:	571134  

__________________
Tim Corcoran
  #2  
Old 08-11-2021, 02:04 PM
mgarblik mgarblik is offline
Ultimate Warrior
 
Join Date: Mar 2005
Posts: 6,035
Default

That is more or less the "Mopar" master cylinder used by just about everyone. Did you pop it apart and see if one of the lip seals may have been put on a piston backwards? It's possible they made a run of hundreds of them with the same defect. If you take the snap ring off and pull it apart, take a look at the seals. At the closed end of the cylinder there should be a piston with 1 seal, the lip toward the closed end. That makes one closed chamber. The second and third lip seals face each other, creating a second sealed chamber when you push them forward. Make sure the 4 little drillings are open from the reservoir into these two chambers when the cylinder is at rest. That's how they refill when you release the brake and vent as the fluid temperature increases. There is nothing else really inside those simple cylinders. I would recommend buying only a new master cylinder for a race car. Not sure if you are buying re-manufactured ones or not. Good luck with it.

  #3  
Old 08-11-2021, 02:21 PM
Scott65's Avatar
Scott65 Scott65 is offline
Ultimate Warrior
 
Join Date: Jan 2002
Location: Houston, Texas
Posts: 1,991
Default

I used one Summit sells, looks the same as yours. I don't remember the brand, but I think I still have the box. It's been reliable with regards to braking. The caps were difficult to get to seal correctly though. Seems that's pretty common with this style MC though.

__________________
'65 Tempest 467 3650# 11.30@120.31
  #4  
Old 08-11-2021, 03:30 PM
Bill Eveland's Avatar
Bill Eveland Bill Eveland is offline
Ultimate Warrior
 
Join Date: Apr 2004
Location: Glasford Il
Posts: 3,650
Default

Kinda hit and miss with offshore parts, is that a cast iron body? I've got a new one from autozone for $35 thats an aluminum body and its been ok. Id try a differant vendor and cross your fingers.

__________________
Illinois Outlaw Gassers

6.27@107
9.97@131
  #5  
Old 08-11-2021, 03:36 PM
Skip Fix's Avatar
Skip Fix Skip Fix is offline
Ultimate Warrior
 
Join Date: Dec 1999
Location: Katy,TX USA
Posts: 20,541
Default

I have 4 of that type, 3 that brand different piston diameters all seem to work good.

I did have new Wilwood Dynalites after 15 runs not hold pressure an not leaking(why I have a couple of MCs to rule that out) Swapped new calipers and fine.

__________________
Skip Fix
1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever!
1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand
1965 GTO 4 barrel 3 speed project
2004 GTO Pulse Red stock motor computer tune 13.43@103.4
1964 Impala SS 409/470ci 600 HP stroker project
1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs
  #6  
Old 08-11-2021, 08:45 PM
Tim Corcoran's Avatar
Tim Corcoran Tim Corcoran is offline
Ultimate Warrior
 
Join Date: Jan 2000
Location: Willow Spring, North Carolina
Posts: 4,666
Default Need recommendations for a MC

Here are pictures taken of the piston of the last defective unit I removed from the car. I am not so concerned as to why these did not work as what I need to get that will work. Looking for recommendations of one that does work. Thanks.
Attached Thumbnails
Click image for larger version

Name:	Piston 1.jpg
Views:	140
Size:	35.7 KB
ID:	571202   Click image for larger version

Name:	Piston 2.jpg
Views:	143
Size:	64.2 KB
ID:	571204   Click image for larger version

Name:	Piston 3.jpg
Views:	138
Size:	42.3 KB
ID:	571205  

__________________
Tim Corcoran
  #7  
Old 08-11-2021, 08:57 PM
69Goat1's Avatar
69Goat1 69Goat1 is offline
Ultimate Warrior
 
Join Date: Jul 2003
Location: Tahlequah Oklahoma
Posts: 3,054
Default

I use a stock replacement drum brake master cylinder...works great. Strange front disk and rear drum brakes...

__________________
1969 GTO, 3370 lbs, 10.5” tire...
07/31/21 Norwalk 9.42 @ 142 1/4, 5.95 @ 115 1/8th mile 3400 lbs...535 with Junk dinosaur Eheads
  #8  
Old 08-11-2021, 09:40 PM
Tim Corcoran's Avatar
Tim Corcoran Tim Corcoran is offline
Ultimate Warrior
 
Join Date: Jan 2000
Location: Willow Spring, North Carolina
Posts: 4,666
Default

Yeah I don't want to use a big heavy cast iron unit looking for the lightweight aluminum with plastic reservoir, one that actually works

__________________
Tim Corcoran
  #9  
Old 08-11-2021, 09:45 PM
Scott65's Avatar
Scott65 Scott65 is offline
Ultimate Warrior
 
Join Date: Jan 2002
Location: Houston, Texas
Posts: 1,991
Default

Here's the brand Summit has(d). I'm not sure what variety of bore sizes they have, so verify it's available in the bore size you want.
Attached Thumbnails
Click image for larger version

Name:	20210811_203728.jpg
Views:	105
Size:	58.5 KB
ID:	571208  

__________________
'65 Tempest 467 3650# 11.30@120.31
  #10  
Old 08-11-2021, 10:06 PM
Tim Corcoran's Avatar
Tim Corcoran Tim Corcoran is offline
Ultimate Warrior
 
Join Date: Jan 2000
Location: Willow Spring, North Carolina
Posts: 4,666
Default

Bill Eveland

What is the part number for the one you got at Autozone?

__________________
Tim Corcoran
  #11  
Old 08-11-2021, 10:25 PM
chiefbigb chiefbigb is offline
Ultimate Warrior
 
Join Date: Dec 2003
Location: richmond va usa
Posts: 1,479
Default

How are you bleeding them

__________________
Be carefull of the feet you step on today.They may be attached to the a$$ you kiss tomorrow.
  #12  
Old 08-11-2021, 10:35 PM
ErikW's Avatar
ErikW ErikW is offline
Ultimate Warrior
 
Join Date: Apr 2003
Location: White Plains, MD USA
Posts: 1,378
Default

https://www.strangeengineering.net/p...ter-cylinders/

__________________
1964 GTO
501, Edelbrock Heads NA, 3460 lbs.
9.76 @ 137mph
1971 Trans Am Lucy Blue, 11.56 @ 115
1966 LeMans. 462, SD prepped Kaufman D ports. 11.90 @ 112
1976 Trans Am twin turbo 462, SD Edelbrock heads 8.50@159
2009 G8 GT
  #13  
Old 08-12-2021, 08:31 AM
Bill Eveland's Avatar
Bill Eveland Bill Eveland is offline
Ultimate Warrior
 
Join Date: Apr 2004
Location: Glasford Il
Posts: 3,650
Default

Its been awhile, but this is the one they list currantly. Im using one for a 85 chrysler 5th ave. Right around a 1" bore. It looks like cast iron in the pic, not sure how accurate that is.

https://www.autozone.com/brakes-and-...1822/49330_0_0

__________________
Illinois Outlaw Gassers

6.27@107
9.97@131
  #14  
Old 08-12-2021, 09:27 AM
Skip Fix's Avatar
Skip Fix Skip Fix is offline
Ultimate Warrior
 
Join Date: Dec 1999
Location: Katy,TX USA
Posts: 20,541
Default

All of the Strange are larger than 1".

__________________
Skip Fix
1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever!
1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand
1965 GTO 4 barrel 3 speed project
2004 GTO Pulse Red stock motor computer tune 13.43@103.4
1964 Impala SS 409/470ci 600 HP stroker project
1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs
  #15  
Old 08-12-2021, 09:54 AM
mgarblik mgarblik is offline
Ultimate Warrior
 
Join Date: Mar 2005
Posts: 6,035
Default

Thanks for the pics of the "guts". Is that all that was in there? No secondary piston? I see they used a double lip seal in one location. That's a little money saving idea and you can't put it on backwards with two lips on it. Easier for the 4 year old Chinese kid to assemble. Do the seals seem to have some friction in the bore? Just wondering if the wrong size seals for the bore were used. As far as a good brand, hard to say other than just trying various different ones until you get one that works. I use nearly all NAPA parts unless buying direct from a race vendor. Can't honestly say I have never received a defective MC from NAPA. Needed two try's to get a working one on a Sprinter Van a year or so ago.

  #16  
Old 08-12-2021, 11:52 AM
Tim Corcoran's Avatar
Tim Corcoran Tim Corcoran is offline
Ultimate Warrior
 
Join Date: Jan 2000
Location: Willow Spring, North Carolina
Posts: 4,666
Default

mgarblik

You ask how I bled the master cylinder, every way possible. Putting bleeder hoses from the ports and into the reservoir and pumping until clear of bubbles, per the instructions that came with the unit basically pushing in the piston less than one inch and holding for 20 seconds repeated several times until no more bubbles come up and finally I bled it with a MC bleeding tool ( Cardone 10-5000mcb) that forces fluid up through the ports . All worthless as no matter what I do the port for the rear brakes will not build pressure.

__________________
Tim Corcoran
  #17  
Old 08-12-2021, 12:37 PM
Dave Polichena's Avatar
Dave Polichena Dave Polichena is offline
Chief Ponti-yacker
 
Join Date: Mar 2004
Location: Lake Worth FL
Posts: 546
Default

I went through several, even Strange gave me fits. Call Lamb and don't look back.

__________________
Dave Polichena
  #18  
Old 08-12-2021, 01:35 PM
firechickenman's Avatar
firechickenman firechickenman is offline
Ultimate Warrior
 
Join Date: Mar 2003
Location: Savannah, MO
Posts: 1,190
Default

Quote:
Originally Posted by Tim Corcoran View Post
mgarblik

You ask how I bled the master cylinder, every way possible. Putting bleeder hoses from the ports and into the reservoir and pumping until clear of bubbles, per the instructions that came with the unit basically pushing in the piston less than one inch and holding for 20 seconds repeated several times until no more bubbles come up and finally I bled it with a MC bleeding tool ( Cardone 10-5000mcb) that forces fluid up through the ports . All worthless as no matter what I do the port for the rear brakes will not build pressure.
I have found the best way to bleed a master cylinder is to plug both ports, fill with fluid, and pump the cylinder (about 1/2") until the piston can only be pushed in approx. 1/8". If it doesn't get to that point of only being able to depress the piston 1/8" or so, that tells me there is either air still in it or it's a bad cylinder. This method does take a little extra time and sometimes I feel like I'm never gong to get the air out but once it's bled, you can feel confident that you're putting a good part on the vehicle.

Quote:
Originally Posted by 69Goat1 View Post
I use a stock replacement drum brake master cylinder...works great. Strange front disk and rear drum brakes...
Same for me!

__________________
'68 Firebird

463/pump gas/SD 325 E-heads/266-272 SR cam/1050 Dominator/3.73/ET Street Radials/1.37 60'/6.30@108.80/9.93@135.14

Hot Rod Drag Week finishing averages:
2014 - 11.12 @ 118.56
2015 - 10.84 @ 124.97
2016 - 10.56 @ 127.88
2017 - 10.29 @ 130.74
2018 - 10.29 @ 130.53
2019 - 10.16 @ 132.34
2021 - 10.09 @ 132.69
2022 - 10.13 @ 133.07

9.93 run - https://youtu.be/hII0_UlYM4U

  #19  
Old 08-12-2021, 03:45 PM
Skip Fix's Avatar
Skip Fix Skip Fix is offline
Ultimate Warrior
 
Join Date: Dec 1999
Location: Katy,TX USA
Posts: 20,541
Default

I bleed with the plugs too and store my extra full and plugged.

__________________
Skip Fix
1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever!
1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand
1965 GTO 4 barrel 3 speed project
2004 GTO Pulse Red stock motor computer tune 13.43@103.4
1964 Impala SS 409/470ci 600 HP stroker project
1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs
  #20  
Old 08-13-2021, 12:11 AM
Tim Corcoran's Avatar
Tim Corcoran Tim Corcoran is offline
Ultimate Warrior
 
Join Date: Jan 2000
Location: Willow Spring, North Carolina
Posts: 4,666
Default

Today I bought another MC from NAPA it's what NAPA sells for the Dorman M99294 as I can't find an actual Dorman. It pretty much looks like it came out of the same China factory as the ones I have been getting from O'Rileys. Sure enough it's bad too. I tried bleeding just like you (firechicken) said in a vice but no matter what I can still depress the plunger way beyond an 1/8". Tomorrow I will head for pick a parts and get a used one off of a car.

__________________
Tim Corcoran
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 04:09 AM.

 

About Us

The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Founded in 1991, it was also the first online forum for people to gather and talk about their Pontiacs. Since then, it has become the mecca of Pontiac technical data and knowledge that no other place can surpass.

 




Copyright © 2017